1. Field of the Invention
This invention relates to an improvement in a thin-film perpendicular magnetic recording and reproducing head for a computer, tape, picture recording, etc. More particularly, it is a thin-film perpendicular magnetic recording and reproducing head which comprises a magnetic member for a return path adapted to face a magnetic recording medium, and having orthogonal grooves filled with a non-magnetic material, and a plurality of layers formed one upon another immediately above the intersection of the grooves, and which exhibits improved output characteristics attained by the exposure of the magnetic member on its side facing a main magnetic-pole film and along the track width.
2. Description of the Prior Art
A thin-film perpendicular magnetic recording and reproducing head (hereinafter referred to simply as "thin-film magnetic head") generally has a very small magnetic circuit and employs a thin magnetic film having a high permeability and a high saturation magnetic flux density, and is, therefore, suitable for achieving a high recording density. It has a high degree of dimensional accuracy and yet is inexpensive, as it is manufactured by a process based on semiconductor technology. This type of head is, therefore, expected to become a main type of perpendicular magnetic head.
The thin-film magnetic heads include an inductive head which is used for recording or reproducing, and a head of the magnetic resistance effect type for reproducing.
Reference is made to FIGS. 5(a) and 5(b) of the accompanying drawings, which are a schematic front elevational view showing that surface of the transducer portion of a known thin-film head which is adapted to face a magnetic recording medium, and a perpendicular sectional and side elevational view of the head, respectively. The head comprises a magnetic member 10 composed of e.g. soft ferrite, a non-magnetic material 3 forming a gap layer, a thin-film conductor coil 4, an insulating film layer 5, a thick magnetic film 7 formed from e.g. a Permalloy, Sendust, or amorphous cobalt alloy and serving to prevent the magnetic saturation of a main magnetic-pole film during recording, the main magnetic-pole film 8, and a protective film 9, which lie one upon another as shown in FIG. 5(b).
In this type of head, a plurality of layers have ends exposed in a surface facing the magnetic recording medium 30, and the magnetic member 10 for a return path to the recording medium 30 has a groove 2 which is filled with the non-magnetic material 3. The non-magnetic material 3 and the magnetic member 10, however, have therebetween a boundary plane 12 which is parallel to the main magnetic-pole film 8, as shown in FIG. 5(a). This arrangement allows the magnetic flux produced by the main magnetic pole to return only to the surface facing it, and disables the head to produce a satisfactorily high reproducing output.